Transmission of light through waveguides has been used for many types of applications. Light signals offer potential advantages over electronic signals. Light can be input from a variety of sources.
Optical spectroscopy, for instance, is useful in a variety of fields, such as physics, astronomy, chemistry, biology, and medicine, among others. Raman spectroscopy, for instance, can use a laser to produce light that interacts with a sample to produce frequency-shifted light, thereby providing an optical fingerprint of the sample's molecular structure. Using such a system, for instance, requires an ability to collect and identify the optical fingerprint.